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1 Persei, HD11241, HIP8704, HR533

1 Persei is a blue eclipsing/detached system main sequence dwarf star that can be located in the constellation of Perseus. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

1 Persei's Alternative Names

The Id of the star in the Yale Bright Star Catalogue is HR533. HIP8704 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD11241.

1 Persei has alternative name(s) :- , V436 Per.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 1 Persei with it shortened to 1 Per.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+54 396.

More details on star alternative names can be found at Star Names.

Location of 1 Persei

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For 1 Persei, the location is 01h 51m 59.31 and +55° 08` 50.7 .

Proper Motion of 1 Persei

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving -9.18 ± 0.23 miliarcseconds/year towards the north and 12.05 ± 0.33 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is -5.40000 km/s with an error of about 2.00 km/s .

1 Persei Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 2644.2700000 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature) of 1 Persei

1 Persei has a spectral type of B1.5V. This means the star is a blue main sequence dwarf star. The star is 7662.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24990.6354172800000000s. The star has a B-V Colour Index of -0.17 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 14,786 Kelvin.

1 Persei Radius has been calculated as being 3.51 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,441,775.15.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 4.42. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

1 Persei Apparent and Absolute Magnitudes

1 Persei has an apparent magnitude of 5.53 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of -1.96 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.46. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to 1 Persei

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.17 which gave the calculated distance to 1 Persei as 1028.91 light years away from Earth or 315.46 parsecs. It would take a spaceship travelling at the speed of light, 1028.91 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 2.52 which put 1 Persei at a distance of 1294.30 light years or 396.83 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

The star's Galacto-Centric Distance is 7,662.00 Parsecs or 24,990.64 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of 1 Persei

The star is a eclipsing/detached system Beta Persei (Algol)/Detached Systems (subtype) variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. 1 Persei brightness ranges from a magnitude of 5.900 to a magnitude of 5.450 over its variable period. The smaller the magnitude, the brighter the star.

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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1 Persei Facts

Visual Facts

Alternative NamesHD 11241, HIP 8704, HR 533, 1 Per, BD+54 396, V436 Per
Star Type main sequence Dwarf Star
GalaxyMilky Way
Absolute Magnitude-1.96 / -2.46
Visual / Apparent Magnitude5.53
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)01h 51m 59.31
Declination (Dec.)+55° 08` 50.7
Galactic Latitude-6.71 degrees
Galactic Longitude131.57 degrees
1997 Distance from Earth3.17 Parallax (milliarcseconds)
 1028.91 Light Years
 315.46 Parsecs
2007 Revised Distance from Earth2.52 Parallax (milliarcseconds)
 1294.30 Light Years
 396.83 Parsecs
Galacto-Centric Distance24,990.64 Light Years / 7,662.00 Parsecs
Proper Motion Dec.-9.18 ± 0.23 milliarcseconds/year
Proper Motion RA.12.05 ± 0.33 milliarcseconds/year
B-V Index-0.17
Radial Velocity-5.40 ± 2.00 km/s
Semi-Major Axis7389.00
Stellar Luminosity (Lsun)2,644.27
Spectral TypeB1.5V
Colour(B) blue

Variable Star Details

Variable Star ClassEclipsing/Detached System
Variable Star TypeBeta Persei (Algol)/Detached Systems (subtype)
Variable Magnitude Range (Brighter - Dimmer)5.450 - 5.900

Estimated Facts

Calculated Effective Temperature14,786 Kelvin

Sources and Links

SIMBAD SourceLink

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